What is meant by heuristic optimisation, Database Management System

Assignment Help:

What is meant by heuristic optimisation?Discuss the major heuristics that are applied during query optimisation.                                                                                       

Ans:   In heuristic opimization, heuristics are employed to decrease the cost of optimization in place of analyzing the number of dissimilar plans to find out the optimal plan. For instance A analyzing optimizer would make use of the rule 'perform selection operation as early as possible' without finding out whether the cost is decreased by this transformation.  Heuristics approach generally assists to reduce the cost but not always. The heuristics which are applied during query optimization are:

a)      Pushes the selection and projection operations down the query tree

b)      Left-deep join trees- convenient for pipelined evaluation

c)       Non- left-deep join trees


Related Discussions:- What is meant by heuristic optimisation

What is the role of order by clause, What is the role of ORDER By Clause? ...

What is the role of ORDER By Clause? ORDER BY clause: The ORDER BY clause permits you to sort the records in your result set. The ORDER BY clause can just be used in select s

Define multivalued dependency, Define multivalued dependency.  What do unde...

Define multivalued dependency.  What do understand by trivial multivalued dependency?  Ans: A multivalued dependency is a full constraint among two sets of attributes in a rela

Describe the major steps in the implementation process, Question: (a) ...

Question: (a) One of the steps in the five-step problem-solving model is implementation. Implementation is considered a key step in the problem-solving model. A problem may be

Relational algebra, Consider the relation schemas as follows. works (per...

Consider the relation schemas as follows. works (person name, company name, salary); lives (person name, street, city); located in(company name, city); managers (person name

4, explain the level architectures of the database management system

explain the level architectures of the database management system

Authorisation, Authorisation Authorisation is the culmination of the ad...

Authorisation Authorisation is the culmination of the administrative policies of the organisation.  As the name shows, authorisation is a set of rules that can be used to verif

What is the use of union and intersection operation, What is the use of Uni...

What is the use of Union and intersection operation? Union: The result of this operation contains all tuples that are either in r1 or in r2 or in both r1 and r2.Duplicate tuple

Prepare an erd for the scenario, Question: (a) Prepare an ERD for the s...

Question: (a) Prepare an ERD for the scenario given below. (b) Convert the ER diagram produced in (a) above into its physical design. You have to choose an appropriate Pri

What is catalog in dbms, What is catalog in DBMS? Catalog - A relationa...

What is catalog in DBMS? Catalog - A relational DBMS maintains information about every table and index in which it contains. A catalog is a collection of special tables that st

Explain physical and logical independence, Define Physical and Logical inde...

Define Physical and Logical independence  Ans: Physical data independence: The ability to modify physical level without causing application program to be rewritten. Logic

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd